How to use a multimeter to detect commonly used electronic components?
Whenever the circuit board fails to operate normally and the circuit is checked and there are no issues, it is highly likely that electronic components are broken. If you want to repair it, you must find the faulty component and replace it. However, finding the faulty component is a technical task and there are also certain skills. Today, we will teach you how to use a multimeter to detect some commonly used electronic components.
Resistance detection
The most direct method to detect resistance is to use a multimeter resistance range for measurement. Generally, the resistance is marked with the appropriate resistance range, and the red and black probes are connected at both ends. If the reading is close, it is normal, otherwise it will be damaged. When measuring large resistance, it is important to avoid touching the red and black probes with both hands. This is not a risk of any issues, but to ensure the accuracy of measuring resistance. It is possible to touch one of the probes with your hand.
Potentiometer detection
Usually, a potentiometer has three pins. First, use a multimeter to select a resistance range to test whether the resistance between two of the three pins of the potentiometer is equal to or close to the resistance value marked on the potentiometer. If there is a significant difference, it indicates that the potentiometer is damaged. If the multimeter continues to measure these two pins normally, then rotate the potentiometer counterclockwise to the close position. At this point, the resistance value should be as small as possible, and then rotate clockwise to gradually increase the resistance, Rotate until the final resistance value approaches the marked resistance value, then the potentiometer is normal.
Fixed capacitor detection
In addition to using a multimeter to select a suitable range for measuring capacitance, a resistance range can also be used for measurement. When measuring, the appropriate resistance range should be selected, and two probes should be connected to the two pins of the capacitor. The resistance value should be infinite. If the resistance value is 0, the capacitor will be damaged.
Electrolytic capacitor detection
There is a slight difference in the measurement method between electrolytic capacitors and fixed capacitors. Of course, you can choose to use a capacitance level for detection. Everyone knows how to use a resistance level for measurement. Firstly, choose an appropriate resistance level, with the red and black probes touching the two poles of the capacitor respectively. At this point, the displayed value will increase from 0 until the overflow symbol 1 is displayed. If 0 is always displayed, it indicates an internal short circuit in the capacitor, If 1 is always displayed, it indicates an open circuit between the capacitor poles, and it is also possible to choose a resistance range that is not suitable. It is important to note that during measurement, as the electrolytic capacitor has positive and negative poles, it must not be connected in reverse. Usually, the red lead is connected to the anode of the capacitor (the one with the longer foot), the black lead is connected to the cathode of the capacitor (the one with the shorter foot), and the pointer multimeter is the opposite.
Inductance detection
Similarly, select the resistance range of the multimeter and connect the probe to both ends of the inductor. If the measured resistance value is zero, the inductor will have an internal short circuit. Under normal circumstances, the DC resistance of the tested inductor is directly related to the diameter of the enameled wire used for winding the inductor coil and the number of wire turns. As long as the resistance value can be measured, the inductor can be considered normal.
Diode detection
Set the multimeter to the detection diode position, connect the red lead to the anode of the diode, and the black lead to the cathode of the diode. If the voltage drop of the diode is displayed on the display screen (usually 0.5 for silicon tube and 0.2 for germanium tube), it indicates that the diode is normal. Change the lead, and if the display screen shows 1, it is normal. Otherwise, it will be broken. If both test results are 0 or 1, it indicates that the diode is damaged.
